So they are 2 weeks old? They do look a touch behind. For their age are you going by when they broke ground? You really don't need to give them any nutes at this stage. That second one looks like it has nute problems and I think it was the fourth that had some twisting on the leaves which could also be a sign of nute stress. I killed seedlings at 2-3 weeks old by feeding. Trust me the soil has enough in it for at least the first few weeks. Now I don't feed until they are about five or six nodes into their growth. I even saw a thread where a guy uses Miracle Gro organic choice and vegges for 5 weeks with no nutes. Then he uses nothing but high phosphorous bat guano for flowering. His buds were amazing and the growth was strong all through veg. I just started making compost tea, and let me tell you, that stuff is amazing. I'll brew some up using composted cow manure and bat guano. Sometimes I'll also put in fox farm nutes since I have a couple bottles of their stuff. The concentrated nutes can be tricky though. My avatar is from my very first grow. Never fed her any nutes except for sucunat. She was slow growing though. She was super short, but with sativa like leaves and flowers, so it took forever to fill my grow box. Then two weeks before flowering I cut off about 30-40% of her branches to allow for better airflow and light distribution. She took 97 days to flower and could have gone longer. Partly because I had her on a 13/11 schedule for flowering. I didn't realize this would extend the flowering stage. I also vegged her for over 2 months. I kept an even canopy by LST'ing and she had 18 or 19 main branches. Finished with over 2oz.
Sorry, got a little side tracked there. Thinking about it again though maybe you should start over, but I'd give them at least another week before I made my final decision.
Also here is a pic of my current grow at exactly 2 weeks
now here are some pics of my last grow at two weeks that was suffering from extremely cold temps and nute stress. They all eventually died.
Sorry for the hijack here. I just like being thorough in my explanations